In this project we are trying to study the cellular and molecular basis of autoimmune diseases with two purposes. First, we want to establish the pathogenic role and antigen-specificity of T cells that cause autoimmune diseases such as multiple sclerosis, myasthenia gravis, insulin-dependent diabetes, among others. Second, we would like to determine the feasibility of specific antigen-induced apoptosis as a means of treating such autoimmune diseases. To these ends, we have made progress in the following areas: 1) we have successfully established the marmoset model of experimental allergic encephalomyelitis at the NIH; 2) we found that antigen treatment of the marmoset disease leads to amelioration of clinical, radiological, and pathological indices; 3) we have optimized an assay for detecting T cells that are activated and secrete gamma-interferon in response to myelin protein antigens and have obtained preliminary evidence that such cells are increased in multiple sclerosis patients compared to normal controls.